Method of continuous casting



Q 26, 1954 J. B. BRENNAN 2,692,411

METHOD OF CONTINUOUS CASTING Filed March 12, 1951 Fig. 5

IN V EN TOR.

Patented Oct. 26, 1954 UNITED STATES 'OFFICE METHOD OF OONTINUOUS CASTING Joseph B. Brennan, Cleveland, Ohio 2 Claims.

This invention relates to continuous casting whereby a lamination of two or more metal strips or shapes is produced by passing a carrier mold and one or more metal objects or strips to be laminated through a body of molten metal and a heating zone and subsequently through a forming and solidification die.

According to my invention, a lamination of metal may be applied continuously to another metallic article, the article on which the lamination is applied being in tubular, strip or other form.

Itis also to be understood that the principles of the invention may be applied and the objects thereof may be achieved in the casting of ceramic material, quartz, mica, germanium, silicon, glass, and other fusible materials, as well as in the casting of metals. For example, a lamination of ceramic material may be applied to a metallic base material, or a metallic material may be applied to a ceramic base material, it being possible according to my invention to laminate any base material having a melting point higher than the melting point of the material from which the lamination applied thereto is cast, the cast material, in the case of a metal cast around a ceramic core, adhering around said core by shrinkag and to some extent by flow of the metal into any surface irregularities and pores of said core. Of course where a chemical bond is desired, well known bonding agents may be employed between the metal and ceramic.

Insofar as common subject matter is concerned, this application constitutes a continuation in part of my pending applications Serial No. 147,466, filed February 18, 1950; Serial No. 201,171, filed December 16, 1950; and Serial No. 202,707, filed December 26, 1950, and Ser. No. 25,756, filed May 7, 1948, now Patent No. 2,569,150 granted September 25, 1951.

In my prior patent applications aforesaid, I described in detail a method of casting whereby a carrier core or mold is passed through a pool of molten material and through an adjacent cooling die; and, in these application, I described the various means and modifications whereby various shaped objects could be cast. In this, my present invention, I propose a method of casting whereby a laminated product may be obtained in a simple and efiicient manner using similar principles.

A feature of this invention is the continuity which may be obtained by my laminated casting method.

A further feature of my invention is the passage of the carrier mold and the article to which the lamination is to be applied through the body of molten material and an adjoining forming and solidfication die after having the lamination cast thereon.

Another object of my invention is to cast a laminated object in accurately controlled dimensional sizes.

A further advantage of my invention is the saving in cost which I efiect by the practice of the invention and the eas by which I obtain laminated casting highly desirable for use in the metal art field, such as, for example, in bearing manufacture.

Further objects and advantages of my invention will become more apparent as a description of the drawings proceed.

To the accomplishment of the foregoing and related ends, said invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principal of the invention may be employed.

Referring now to the drawings annexed hereto.

Figure 1 is a sectional and elevational view of apparatus whereby the method of my invention may be practiced;

Figure 2 is a cross sectional view of a tubing or bushing which may be obtained by the practice of the method illustrated in Figure 1.

Figure 3 type of mold and the article thereby secured according to my invention; Figure 4 is a variation of Figure 3.

Figure 5 illustrates a laminated strip obtainable by the practice of my invention.

Further referring to Figure l, the mandrel or carrier mold 2 is passed through the bearing sleeve 3 located upon the extending arm I which is attached, for example, to the crucibl 5 at the point 4. As the mandrel or carrier mold 2 is passed downward through the bearing sleeve 3, the metallic sheet 6 is unwound from the drum l rctating upon the axle 8 and is moved downward over the guide wheels 9 which direct the metallic sheet 6 toward and around the mandrel or carrier mold 2. The rollers In complete the tubular forming process of the metallic sheet 6 around the mandrel or carrier mold 2.

If preferred, the tubular form 6 may be made and fed down without the core 2 moving and the core 2 may be of metal or ceramic material.

The carrier mold or core 2, instead of being is a cross sectional view of another in the form of a cylindrical mandrel, may be square, rectangular, triangular, or it may be of other flat or curved or angular sided shape. This will permit the utilization, for example, of an entire width of steel; also, if desired, it will facilitate slitting of the laminated article into fiat strips. In preference to the steel drum 7 and the rollers 9 and In, it is possible in the practice of the method herein disclosed to form the metal 6 around thecarrier. r'nEil'dJiin the m anrier heretofore described'in' my prior applications. In such instance, the sheet 6 would be cast around the carrier mold 2 by passage of the mold 2 through a body of molten metal and subseguentlynthrough a forming and solidification die and after the sheet 5 has been cast about the moldor'core 2,

the mold 2 with the sheet 6 cast therearqund is.

such as is shown in application Serial. No.

202,707. Or the mold may consist of a series of divisible molds stacked in aligned relationship in a manner such as is shown in my application Serial No. 202,707. aforesaid.

Further. thefmandrel, orv core form 2, which is fed through the poolof molten metal may be destructible or. it may be of a'ser aaem core, or mold nature. After the sheet 6. hasibeen formed aroundfthe moving carrier. core: 2:. by. the/rolls Ill, the carrier core Zandencompassing sheet 6, for. example, are further. moved downward into the body. or pool of molten metal I I. 'I-heftemperature of the moltenfmetal. H and the. sheet ii is maintained by the, electrorconductiye. coils 12.

As the carrier mold or. mandrel 2. andthe sleeveform 6.. pass through the molten metal, ll the l n m t l n' ame d a d p e t he forming, and solidification die/i4; The sheet, 6 and the sleeve 6 become heated to, the, tempera.-. e of the mo ten met l Theb-utsideo formed nie ialfbas'e 6 is. spaceda. di tance, which. corresponds to the thickness of the desired 1am; inated layer [3, provided, between the outer Sm: face'of'the sheet 6 andthe innersurface ofthe forming and solidification die ['4 magna e centrally therein. As the heated formed metallic sheet e and the molten metal I l therearound. further proceed downward] into; and through the forming and solidification, die IA, the molten. metal l l solidified and; thermally bonded to the steel, and the laminated layer 13 is bondedv over and around the' sheet. 6} The solidification portion 14b of the die' IA- is controlled, for-example, in temperature by the exterior cooling coils d located the cooling die: 15. Alternatively, other cooling meansrnay be'mployed for purposes of; this inventionf'Asthe rnolct 2; the metal layer 6-, and the laminated layer- I3 complete their passage through the. forming andsolidification 'die M; inside the "cooling-die 15 the desired lengthsmay be cut off bymeansof the cut on" tool 16. I111 anyevent the laminatedlayer is pre-formedinv a. molten condition around the. metal to. be i laminated and solid'ified: thereon. Cooling means. may. also. be incorporated insidemandrel 2,

In the particular example of the invention which I have described in Figure 1, it should be understood that a guide tube or unit molds (not shown) such as I have disclosed in my application Serial No. 202,707, filed December 26, 1950; also may be adapted to the process of this invention. The splines to which I have made reference therein may also be used herein for purposes of guiding the carrier mold or core g through the body of molten metal and aligning the earrier mold or core 2 with the metallic sheet form 6 thereon with reference to the forming and solidification die. Here again, if it is desired to produce laminated. strip. material where a central mold is employed, the splines may extend into the zone of solidification, the splines here also being spaced apart a distance corresponding the desired width of the laminated cast strip. The splines may beemployed with or without a clear ance allowance for fins between the strips. Where no allowance is made for these fine, a tension means is desirable-in order-to aid the withdrawal of the strips from the solidification die,

The cast metal lamination may he applied w the in de r ts e; er nl p ially o v rface,- or it may be applied to, both surface of a tubular, fiat, Or rod, or other shape material. Where a tube is cast, the resultant, tube may be opened and flattened. or otherwisev rershaped such as by reforming it toenclose the externally depositedand bonded metal; on the inside.

Also when a lamination is cast externally over or on a piece of steel, as shown in Figure l, the laminated product maybe. divided into one or more stripsprior to lamination orit. may be split openfon the. seam and flattened out, aiter. lamination.

The distancev oi heat. application alqmye the coolingzone may be regulated to. the rate. oi cooli g. Lengthwise chilling may be effected by endw'ise. cooling. Also, the. distance. of travel, while enclosed, in the, solidification zone may be regulated.

Ashas been previously. explained, the, tube 6 may be, castin apreceding crucible casting setup. This. arrangement. is particularly desirable. where a laminated seamless tubing iswanted.

i i fi torbe un e odihat am na ed W511.- v h m n ures c elt ma ta ma h: oddescribed herein, in a manner similar to that. scribed f in, my. arhli atign Seria 292 707 filed December 26, 1950.

It must, be e s hat; t Possible t ake o e s am na 1 mm g 9 1. g 0. t l n a a nd haw 2. Ti taproduqe mn s- 0 f e er llic: ob e ts. he len th. of thejfinished laminated. product, can b 111. t1'o1led.;by-. r n .eans oithe. cutofifi-tool. i 5,

A. per 9th:: example. of! 36 v t e r si es. in the fact that there is a forming section for; thev a s n e a s This f rmin e onr s above the di: ga ge zo e an bene th t n. m t neck and: s: ndicated t. W. Fisml h prmed 1amir t qn. r or o l-id. ti ni b ng. nd a d; ea Howeven. whe a de be; is empl y d, this forming section; may extend; up into the. molten; metal; pooh its lf:

s: a so possible to produce. laminated. tubin according to invention by'having the. core: mandrel; 21; Eigure, l1, stationary and: ending at the. point shown; by. the diametric dottedzline. below the cooling die. [4, Figural, in: which modification the produced lamination will be withdrawn by tension rollsor other means not shown below the. solidification zone 1-5: and outside thereof:

It is also possible according to my invention to have mandrel 2, Figure 1, rectangular or square or other shape and to draw strips thereover through the pool of molten metal and thereby cast and bond a lamina of molten metal on each strip.

It is also possible to modify the forms shown in Figure 3 and Figure a so as to enclose the core 2 of Figure 1 having cast or applied metal over core 2 and to use the half molds of Figure 3 and Figure 4 as enclosures for a single or double layer of metal cast about core 2. In this variation the forms 20 and 2! of Figure 3 and Figure 4 would be hollow half cylindrical shells and pass through the molten pool ll, Figure 1, guided and spaced around core 2 and thereafter in exterior contacting relationship with the cooling die l4 and have the cast tubular meta-l therein in single or double layer as desired. This arrangement could be used with core 2 moving or stationary and ending just below cooling zone l5, Figure 1. In this way it is possible to cast tubing continuously of single or double thickness. It is necessary to have 2 pools of molten metal and the solidification zones associated therewith one over the other ltO cast a double layer of metal tubing. In this case the core 2, Figure 1, may be stationary or moving as explained above.

In the practice of my invention wherein a metal lamination is applied to a metallic material, the base metal to which the lamination is applied has a melting point higher than that of the metal employed for the lamination casting.

Referring to Figure 2, the finished product pr duced by the method and apparatus of Figure 1 is shown in cross section. The metallic sheet 6 has the laminated layer it thereover. The slit I? in the metallic sheet 8 can be eliminated, Where desired, by a prior passage of the formed sheet 6 through a welder to Weld the edges of the seam and thereafter casting the strip 6 therearound.

In Figure 3, I have illustrated a further adaptation of my invention. In this instance the metallic strips l8 and it, as of steel, for example, are located within and edge gripped if desired by the opposed aligned sectionalized carrier mold parts 20 and 2!. This type of mold is similar to that described in my application Serial No. 201,171, filed December 16, 1950, and may consist of two annular rings or two straight pieces; the practice of the method with this type of mold is similar to that previously described in my application Serial No. 202,707, filed December 26, 1950. The strips l8 and 19 are located within the opposed aligned molds 2d and 2| and are passed through guides and beneath the surface of the molten metal H in the crucible 5. Passageways 27 and 28 are shown which extend from the exterior of the carrier molds 20 and 2| to the cavities defined by the complementary portions of the molds 20 and 2! and the metallic strips i8 and i9. These passageways may be constructed in any conventional manner, and as heretofore have been described in my aforesaid applications. The molten metal then flows into the cavities located between the strips it and It and the interior of the molds 20 and 2|, Thereafter, the strips 58 and I9 and the molds 20 and 2! are passed through the die M with its exterior cooling section if whereupon the cast facings or larninations 22 and 23 is solidified. Upon solidification there are formed the laminated layers 22 and 23, for example, of bronze. When the mold sections 20 and 2 I, securely holding the steel strips i8 and i9 therebetween, are passed through the pool of molten metal ii and the high frequency field created by the coil l2, the steel strips become heated to a bonding temperature so that when the metal laminations 22 and 23 are cast thereagainst, a good bond is obtained. A temperature from 2100 F. to-2300 F. is generally suitable when applying bronze to steel. In efiect according to the apparatus shown in Figure 3, it is possible to pass two straight carrier bars or molds 20 and 2i which correspond to the carrier mold or mandrel 2 in Figure 1 through the molten metal pool II and then through the so forming and solidification die It.

Figure 4 illustrates a method similar to that described in reference to Figure 3. In this in stance a single metallic strip 24, as of steel, is located between and held by the complementary portions of the opposed aligned molds 20 and 2!. The molten metal here flows into the molds 2i and 2! through openings 2i and 28 and the laminated facings 22 and 23 are cast and formed on the opposed surfaces of the strip 2 2 in a single operation.

The mold halves 20 and 21 in Figures 3 and 4 and the core 2, Figure 1, may be carried by chains or hydraulic pushers through the molten metal pool i l and the forming zone Mia and through the solidification zone It, Figure 1, for the pur poses of this invention.

Figure 5 illustrates a laminated cross-sectional strip which may be produced according to this invention and consists of a single metallic strip 25, as, for example, steel with the cast lamination 26 of, for example, bronze bonded thereto. The article of Figure 5 may be produced according to the method described in reference to Figures 3 and i and 1. The strip 25 in this instance extends a distance equivalent to the diameter of the molds 2B and 2i. The laminated layer :26 cast thereon corresponds in width to the width of the strip 25. In this case, the lamination is applied to only one face of the base steel strip. Spline and center spacing guides may be used in the molten metal pool and above it to align the steel strip and the mold sections.

In some cases it may be desirable to pass solid cast tubing or welded tubing through the pool of molten metal for lamination. In some cases it may be desirable to coat between the inside and the exterior surface of steel tubing for example with laminated metal. This can be done by extending the depth of the metal H, Figure l, and the crucible 5, Figure 1, and the high frequency coil 52, Figure l, upward to encompass and enclose rolls Ill, Figure 1, and by reducing the di-- ameter of the mold from 2 and holding it in interspaced relationship from the steel 6 to permit the molten metal to flow inside the steel strip 6 as it is formed about the mold 2.

In case the molten metal is cast inside the steel strip 6 as it is being formed about the mold 2, this zone preferably must be kept above the melting point of the metal being cast. The mold 2 in this case should terminate in the cooling zone in case it is stationary, to reduce the friction due to shrinkage of the cast metal about the mold 2. The mold 2 may also in this instance be reduced in diameter by tapering progressively as it extends down through the cooling zone to eliminate adherence of the cast metal thereto.

Other means of introducing the metal to the interior as well as to apply it to the exterior and to bond the metal thereto will be apparent to assent-r which I have taught herein, the above examples being illustrative only of some methodsof acecomplishing the. resultof my invention.

It. is also; to be: understood that-the apparatus.

of this. invention may be enclosed in variable pressure apparatus (not. shown) such as isdis-- closed and described in my pending: application Serial No. 202,707, filed December 26-, 195.0,. and my prior Patentv No. 2 ,37l,.6l04;,.issued March 20., 1945.. Such variable pressure apparatus very readily may be employed in, conjunction, for ex.- ample, with the apparatus of Figure 1. Where such variable pressure appar us isused t practies the art of my inventiomthe lamination cas.t ing disclosed herein then may be carriedout under pressure. or vacuum or under a controlled atmosphere in much the manner described in. my application Serial No. 202,707 aforesaid.

It is possible with the apparatus and by the method of my invention to castv oxygen free metal laminations. The air of the atmosphere or other gaseous. impurities may be removed and a vacuum created in the variable pressure apparatus, and where it is desired to; cast. undera pressure other than that of a vacuum,, an inert gas may be supplied to, thevariable'pressure apparatus. Impurities, such as oxides, can be reduced and converted into pure metal by bubbling a deoxidizing gas, such as. carbon. monoxide, through the molten metal in the manner described in my Serial No. 202,707 aforesaid. In addition, a. vacuum may be used to remove or to. aid in the removal of the gaseous impurities from the molten metal or to eliminate the presence of free oxygen in the variable pressure chamber:

It is to be understood that. the base or core 2 may be stationary and need not move with the base material 6 to which the lamination is tobe applied. In this instance, the stationary core passes through the crucible containingthe molten material and only through the. forming and solidification die.

It will be understood that the invention is. not limited to the specific examplesv set forth Since modification may be resorted to within the scope of the invention.

Having thus described my invention what I claim:

1-. A. method. of producing laminated material from. a. strip; of material and a pool of molten metal contained in a. vessel having an open-ended die below the level of the molten metal in the vessellandalaterally fixed, relatively rigid mandrel'projseeting into said die in accurately spaced relation thereto, comprising forming a hollow member on said.- mandrel from strip material, which formsone lamination of the finished material, moving the member, guided by said mandrel: into. and through the pool to. heat the member toabonding temperature and continuing the guided: movement of said member into said die, where the second laminating element solidifieson the member.

2; Arnethodof producing laminated material from a strip. of material and a pool. of molten metalcontained in a vessel having an open-ended die below the level of the molten metal in the vessel; and a laterally fixed, relatively rigid mandrel projecting into said die in accurately spaced relation; thereto and projecting through the vesseh comprising forming a hollow member from strip materiahwhich forms, a laminating element of. the finished material, moving the member-,. uided by. sa d mandr l, into and through the pool to heat the member to bonding temperature, continuing the guided movement of said member into said; die, where the second laminating element solidifies on the member, and. longitudinally splitting; and flattening the composite-member and solidified laminating element. to produce-laminated material in strip form.

fleferenws Cited in the file of this patent UNiETED STATES. PATENTS.

Number Name Date 124,911 Newton Mar. 26, 1872 1,995,258 Stockileth Mar. 19, 1935 199-9114 Sherwood Apr. 23, 1935 2,055,980 Liebmann Sept. 29, 193.6 2,092,284 McCarroll' et al. Sept. 7', 193.7 2,128,942 Hudson Sept. 6', 19.38 2338,7131 Porter Jan. 11, I944 

